Effect of divalent manganese (Mn2+) concentration on the growth and nitrate nitrogen content of lettuce during aeroponic intercropping with cherry radish

• Published in: Horticulture, environment and biotechnology Vol. 62; no. 2; pp. 243 - 251
• Main Authors: Zhang, Lei, Wang, Linlin, Li, Faqinwei, Xiao, Fei, Yu, Haiye
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.04.2021; Springer Nature B.V; 한국원예학회
• Subjects: Aeroponics; Agricultural practices; Agriculture; Biomedical and Life Sciences; Buffers; Intercropping; Lettuce; Life Sciences; Manganese; Metabolism; Nitrate reductase; Nitrates; Nitrogen; Nitrogen metabolism; Nutrient concentrations; Nutrient solutions; Plant Breeding/Biotechnology; Plant Ecology; Plant growth; Plant Physiology; Radishes; Reductases; Research Report; Stomata; Thresholds; Vegetables; Weight; 농학; Lettuce; Nitrate; Nitrogen metabolism; Intercropping aeroponics; Nitrate reductase; Manganese ion
• ISSN: 2211-3452; 2211-3460
• DOI: 10.1007/s13580-020-00303-0

Manganese (Mn) plays an important role in regulating metabolism, especially nitrogen metabolism, in plants. Considering the desired levels required for plant growth and the most popular concentration in nutrient solutions in soilless cultures, lettuce plants were exposed to 4 µM, 10 µM, or 40 µM Mn 2+ as MnSO 4 ·4H 2 O during aeroponic intercropping with cherry radish plants with a 1:1 quantity ratio of lettuce/cherry radish. The effects of Mn 2+ on plant growth, nitrate nitrogen (NO 3 − -N), and metabolism of lettuce were investigated. The results showed that the fresh weight (FW) and dry weight (DW) of lettuce increased by 20.9% and 24.7%, respectively, at 30 days after transplanting when the Mn 2+ concentration ranged from 4 (treatment C1) to 40 µM (treatment C3). The NO 3 − -N content in the edible parts of lettuce decreased by 34.4% and 44.9% with increasing Mn 2+ concentrations on the 10th day and the 20th day after transplanting, respectively, but the maximal reduction of the NO 3 − -N content was only 9% on the 30th day when the Mn 2+ concentration ranged from 4  (treatment C1) to 40 µM (treatment C3). Additionally, our results showed that increased but not excess Mn 2+ could markedly promote nitrate reductase (NR) activity instead of limiting the stomata, which was one reason why the NO 3 − -N content in edible parts decreased. During aeroponic intercropping with cherry radish plants, Mn 2+ thresholds were found that improved organic biomass and nitrogen assimilation in the edible parts of lettuce. The Mn 2+ thresholds could be similar or different, but both were within the range of 10  (treatment C2) –40 µM (treatment C3).